Cellulose has three hydroxyl groups (—OH) per anhydroglucose unit. As these hydroxyl groups form regular hydrogen bonds within a molecule, a rigid crystalline structure is formed. Accordingly, cellulose has a stable structure that is not soluble in water or organic solvents.
When some of these hydrogen bonds in cellulose are substituted with an alkyl group, the substituted cellulose has a less rigid crystalline structure compared to unsubstituted cellulose, and thus, the substituted cellulose is converted into a cellulose ether that is a water-soluble polymer.
In order to improve the solubility of the cellulose ether that is a water-soluble polymer into an organic solvent, and to make use of the cellulose ether as thickeners, binders, or materials for membranes such as membranes for water-treatment, Korea Patent Publication No. 2011-0089662 discloses acetylated cellulose ether prepared by introducing an acetyl group into the cellulose ether. However, the acetylated cellulose ether prepared in the above manner has a low turbidity so that the commercial use thereof is limited.